In recent years, an electric vehicle, a hybrid vehicle, a fuel cell vehicle and the like have received attention as an environmentally-friendly vehicle. On these vehicles, a motor that generates driving force for traveling as well as a power storage device that stores electric power supplied to the motor are mounted. The hybrid vehicle further has an internal combustion engine mounted thereon as a power source, together with the motor. The fuel cell vehicle has a fuel cell mounted thereon as a direct current (DC) power supply for driving the vehicle.
Among these vehicles, a vehicle is known in which a vehicle-mounted power storage device for driving the vehicle can be charged from a power supply in ordinary households. For example, a power supply outlet provided at home is connected to a charging port provided at the vehicle by using a charging cable, so that electric power is supplied from the power supply in the ordinary households to the power storage device. It is noted that the vehicle in which the vehicle-mounted power storage device can be charged from the power supply provided outside the vehicle will also be referred to as “a plug-in vehicle” hereinafter.
The standard for the plug-in vehicle is set in “Electric Vehicle Conductive Charging System, General Requirements” (Non-Patent Document 1) in Japan, and in “SAE Electric Vehicle Conductive Charge Coupler” (Non-Patent Document 2) in the United States of America.
In “Electric Vehicle Conductive Charging System, General Requirements” and “SAE Electric Vehicle Conductive Charge Coupler,” the standard for a control pilot is defined as an example. The control pilot is defined as a control line that connects, via a control circuit on the vehicle side, a ground of the vehicle and a control circuit of EVSE (Electric Vehicle Supply Equipment) for supplying electric power from an on-premises wiring to the vehicle (Non-Patent Document 1). Based on a pilot signal communicated through this control line, a connection state of the charging cable, whether or not electric power is supplied from the power supply to the vehicle, a rated current of the EVSE and the like are determined.
When a charging current flowing from the power supply to the power storage device exceeds the rated current of the EVSE, there arise problems such as tripping of a breaker and overheating of the charging cable. In order to address these problems, Japanese Patent Laying-Open No. 2000-232737 (Patent Document 1), for example, discloses that, in a charging apparatus capable of converting alternating current (AC) electric power outside the vehicle to DC electric power by an inverter and charging a secondary battery, charging stops if an input current of the secondary battery does not match a current target value of the inverter for charging (see Patent Document 1).    Patent Document 1: Japanese Patent Laying-Open No. 2000-232737    Patent Document 2: Japanese Patent Laying-Open No. 7-298506    Patent Document 3: Japanese Patent Laying-Open No. 10-285819    Patent Document 4: Japanese Patent Laying-Open No. 11-205909    Non-Patent Document 1: “Japan Electric Vehicle Association Standard, Electric Vehicle Conductive Charging System, General Requirements” Japan Electric Vehicle Association, Mar. 29, 2001    Non-Patent Document 2: “SAE Electric Vehicle Conductive Charge Coupler” SAEJ1772, SAE International, November, 2001